Research and application of pre-stack fast inversion technology based on lithologic data reconstruction
The central part of the Sichuan Basin is a core production area for tight gas,where the Jurassic Shaximiao Formation is an important formation for the exploration and development of tight gas reservoirs in re-cent years.The channel sand body of the Shaximiao Formation exhibits rapid lateral changes,complex vertical overlapping relationships,and strong reservoir heterogeneity,which leads to low accuracy of the inversion method for post-stack wave impedance lithology.Meanwhile,the calculation process of pre-stack lithology in-version is complex and time-consuming and cannot meet the needs of rapid increase in reservoirs and produc-tion.Therefore,the pre-stack fast inversion technology based on lithologic data reconstruction is proposed in this paper.Firstly,by combining both P-wave and S-wave impedance with geological prior information,the li-thology impedance logging curves are reconstructed,the lithology identification threshold is determined and the lithology impedance analytical formulas are established.Secondly,the A VO attribute analysis is carried out to derive the lithologic impedance reflection data expression characterized by intercept P and gradient G,and to re-construct the lithologic impedance reflection data which characterizes a more prominent seismic response.Fi-nally,high-precision three-dimensional lithofacies are quickly obtained through post-stack inversion,which is used as a three-dimensional spatial constraint for subsequent pre-stack geostatistical inversion.The application results of the technologyin a 13,000 km2 contiguous three-dimensional area in the Central Sichuan Jinqiu Block show that this technology can effectively improve the stability and reliability of the inversion process while re-ducing time consumption.The inversion results achieve higher precision and resolution.The match rate be-tween reservoir characterization and actual drilling exceeds 90％,and the success rate for its implementation in the exploration wells reaches 100％.Thus,the application of the technology promotes a high efficiency explora-tion and development of the tight gas reservoirs in the Shaximiao Formation.
tight gas reservoirsAVO attributelithological inversionlithofaciespre stack geostatistical inversion
万方数据
维普
